Tire



May 1', 1945.

B. E. MENDELSOHN' TIRE Filed Sept. 9,. 1941 I V In $771250? $ernay f Mab e/.2945;

gummy ##4 tin 9 n7 varying pl cords running up as high or higher prevent the air from escaping through the shoe to with-stand bursting stresses which occur in chamber 3 is formed by the partition 4 which under excessive pressures so that the fabric in thus completing the formation of the partition.

Patented May 1, i945 I I 1 UNITED STATES ATENT OFFICE d 7 2,375.127 I TIRE! Bernard E. Mendelsohn, Brookline, Mass, assignor of onehalf toB. Howard Benson, Boston, Mass. I Application September 9, 1941, Serial No. 410,183 1 Claim. 152-3391) The present invention relates to tire construcreinforces theshoe about the bead by the addi'-, tion, and in particular to safety tires for use on tion of the number of layers of fabric used in the motor vehicles for both air-crafts and ground partition itself. This method and construction machines. may be employed with a number of modifications. The present invention has for its object the Within the inner partition is the usual inflation, over-coming of certain difliculties which contube which may be joined with the chamber structions of the prior art have been troubled through a release valve which releases under the with. desired pressure. I In all vehicles, and particularly in vehicles Various other and further modificationsjmay: which bear heavy loads or'which are intended to 10 be employed 'withinthe principles of the inven'f-f be driven at high speeds, the stresses on the rubtion as generally described above, but initsprebershoes at times becomes very great. This is ferred form the invention is described below in particularly true with air craft wheels, which connection with the specification and drawing il-f while in use only for very short distances, such lustrated showing an embodiment of the same, in as taking off or landing, never-thej-less must enwhich: dure great stresses at such times, first because of The sole figure shows a radial section through the load of the machine, and secondly, because theshoe and the rim. i f taking off and landing speeds are often consider- Referring to the figure, l represents the shoe ably higher than that of the driving speed of the" which may be built up of any number of plies, ordinary automobile. In addition to this, forced depending upon the use to which theshoe' is to],

landing and imperfect landings are such as to be put. On the inner surfaceof the shoe l ,anon- I stress unduly the rubber shoes of the wheels. leak seal compound 2 of rubber or other suitable Automobile and air-craft shoes are made with material may be used. The purpose of this is to than thirty-six plies in order to be strong enough from the chamber 3. The inner wall of the their use. comprises layers of fabrics 5 and rubber 6 in its The present invention relates to a safety shoe side walls which is non-extensible but flexible in connection with such constructions. The apand a top portion 1 ofpure rubber which is plicant has previously used a shoe in which an mounted or joined at its sides 3 and 9 to theside i air chamber is formed between the shoe itself and fabrics 5. The side fabrics 5 forming the sides internal flexible but non-yielding fabric partiof the inner partition are preferably molded as tion which is anchored about the bead of the a part of the shoe in the formation of the shoe. shoe. This partition, because of the manner in This may be done b moulding and curing the which it is held to the shoe, permits a fairly comside fabrics 5 with the fabrics I 0 and I 0 forming plete deformation of the shoe, for instance when the sides of the shoe, some suitable material bethe machine hits a bump or comes down heavily, ing placed between the fabrics 5 and ID to prewithout putting too great a stress upon the parvent the former from adhering to the side walls tition itself. However, in some cases the conof the shoe. The fabrics 5 in this way have their struction cannot be such as toallow sufficient 40 other ends molded or formed as an integral part deformation to prevent undue stresses upon the of the shoe itself. extending in the form of a flap fabric partition. or apron from the bead H of the shoe when the In the present invention abnormal deformashoe is made. The section around the base is mations are prevented without unduly stressing here referred to as the bead section. the partition. This is accomplished principally The yielding po on '1 0f e inner partition by adding in the top central section in the fab may then be vulcanized or molded to the free ric partition, a yielding flexible section yielding edges of the flaps all the way around the shoe,

the partition will not be unduly strained. In this The extensible rubber piece 7 should be of concase the fabric portions of the partitions may be siderable thickness in comparison to the inner formed and molded with the ply layers of the tube l2 which rests against the inner partition shoe with their inner edges free, permitting the at its inner side. The p p se O s i to p addition of the yielding section after the shoe has mit considerable pressure to be built up within been substantially completed. In this constructh chamber 13 formed y the inn r t e 2 tion the inner fabric partition strengthens and fore the rubber top member I will expand. Ordi- This provision eliminates excessive stresses in the Side fabrics, since in the present construction when the member I stretches, the side fabrics 5 move outward with the bead as the anchor point until the fabrics 5 come in contact with the inner wall of the shoe. The diiferential pressure between the inner chamber I3 and the outer chamber 3 is obtained by means of the connecting valve I 4 between the tube l2 and the external chamber 3. This valve may be of a known construction and comprises a valve stem I5 at the end of which is a piston l6 which sits against the valve seat H. A spring I81 exerts a pressure between the inside of the valve seat 11 and a head l8 formed at the end of the valve stem in such .a way that the piston l6 will not be raised from its seat to permit the air to escape from the chamber I3 to the chamber 3 until the desired pressure, for instance fifteen pounds per square inch is a differential between the two chambers.

The valve may be installed by cementing to the fabric of the side walls, a disc 19 having a bushing 20 into which is inserted the collar element 2| which extends from the disc 22 cemented to the outside wall of the inner tube l2. The chamber l3 may be inflated by the valve 23 in the usual manner and as the pressure in the chamber l3 becomes sufiiciently great so that the valve- I4 opens, the external chamber becomes inflated. -The valve isadjusted so that it will open at a pressure less than thatrequired to expand the rubber element 1 to any great degree so that air begins to flow into the external chamber 3 before any appreciable expansion of the internal chamber occurs, and in this manner the desired ratio of chamber size between the inner and outer chamber is maintained.

If a blow-out should occur, initially the inner chamber will expand and fill out the entire space within the shoe. Subsequent to this air would escape from the inner chamber until its pressure was equal to the established pressure differential in which case the inner chamber would come back to its general normal size and the machine would be run under these conditions maintaining partial pressure on the tires.

The present arrangement also permits ready repair of the external chamber in event that a puncture occurs through the shoe wall. In this case the rubber wall of the internal partition at I may be slit and the leak readily repaired if the repairs cannot be made from the external side. If the rubber partition I is slit a new piece of rubber may be vulcanized or cemented to the piece 1 in the same manner that an inner tube might be repaired. The rubber member I should of course be made of such a thickness that a stretch of the nature required, that is, approximately will not be of such a nature as to decrease the thickness of the member beyond the point where the stress is greater than that permissible under working conditions.

Having now described my invention, I claim:

A pneumatic tire casing for motor vehicles and the like comprising an outer shell of rubber and fabric adapted to fit on the rim of a wheel and having beads adapted to be in contact with said rim, an inner casing having fabric side walls cured tosaid outer casing in said beads and an extensible yielding rubber piece forming the crown wall of said inner casing and joined at both sides to said fabric side walls.

BERNARD E. MENDELSOHN. 

